Method of preparing solid fuels for burning in pulverized form



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' Patented June 12,1928,

UNITED STATES LEE B. GREEN, OF

LAKEWOOD, OHIO, .ASIGNOR TO THE BORDEN COMPANY, OF WARREN, OHIO, A CORPORATION OF OHIO.

unrnop or PREPARING soLrn FUELS Ion BURNING IN PULVERIZED roam.

11o Drawing. Application filed November This invention relates to a method of preparing solid fuels, such as coal, for burning in pulverized fg nLin urne i the type that are now known and used for burning pulverized coal.

In the art of'burning pulverized fuels, such as coal, it is usual to pulverize the fuel and then introduce it into a blast of air in properly .re llated amounts, the mixture of air and uel being then conducted to a a burner b which it is injected into a combustion c amber where the mixture is ignited and burned. In all known forms of apparatus, for this purpose, a supply of the pulver- 16 ized fuel is maintained in a suitable storage reservoir from which it is graduallge fed to the blast ofair, and trouble has en experienced with this method of handling the fuel on account of its explosive nature when 10 in pulverized form. In agitating the pulverized fuel preparatory to feeding it 1nto the blast of air, a highly explosive mixture of air and fuel is produced, and sometimes trouble arises because of an explosion of this I mixture in the fuel reservoir or in the apparatus conveying it to the burner, such explosions occurring frequently as a result of a back-fire from the burner or from aspark which might be created by the friction of parts comprising the feeding apparatus.

Heretofore, onaccount of the dangers which attended the use of pulverized fuel and the necessity for having skilled workmen to operate the equipment, it has been customary to confine the use of pulverized fuel to mills, power plants, and similar places, and it has been considered impracticable to use pulverized fuel in homes, apart-' ment houses, and other places where rela- 40 tively small apparatus would be required.

It is one of the objects of my invention to rovide an improved method of preparing pul verized fuel that will permit the use of pulverized e'l burners in homes, apart- 415 ment housesyand other places where only unskilled help is available and where only what may be termed fool-proof apparatus ma be used. v

1 further object of the invention is to rovide a method of reparing, fuel for urning which will avoi the storage of pulverized fuel adjacent the burner and will '20, 1926. Serial Ho. 149,799.

also avoid the objectionable dusty conditions that prevail around resent installations for burnlng pulverized filel.

A further object of the invention is to provide a method of preparing pulverized fuel that will permit the fuel to be main-- tained in the form of chunks or bri ucts until just prior to its introduction into tie burner, thereby eliminating the danger that has heretofore attended the storage of fuel in the pulverized form.

Another, object of. thcvinvention is to provide a system of pre aring pulverized fuel that will permit the t iiel. to be initially prepared at points remote from the place of use, such as at mines or coal yards, and de livered to tllevpoint of use. in the form of chunks, blocks, or briquets, which may be stored in a coal bin adjacent the point of use in much the same manner that ordinary coal is stored in homes and apartment houses.

Other objects of the invention and-the features of'novelty will be ap arent from the following description wherein I describe what I now consider to be the preferred method of practicing the invention. J

According to my preferred method of practicing my invention, I take ordinary coal, either hard or soft coal, and run it through a pulverizing machine in which it is reduced to a fineness that Will be uniformly less than a predetermined size, such as a fineness that will pass thr ugh what is known as a 200 mesh screen. fillS reference to a specific fineness is mentioned merely by way of example, and as a matter of fact the fineness may be varied within {wide limits.

-However, the largest particlesmust be of a fineness such that they can be carried into suspension and burned if they should be broken loose from the briquet without being reduced by the scra ing or abrading means hereinafter referre to. This pulverized coal is then introduced into an ordinary briquetting machine, together with a suitable amount of binding material, such as .coal tar, where these materials are thoroughly mixed and then compressed into blocks or briquets of any preferred size, and, for'this purpose, I would recommend blocks 6" x 6" x 6'? or 6" x 6" x 12". When soft coal is used,

I prefer to subject the blocks, in the briquettin operation, to a suflicient pressure that wilI tend to bring the oil in the fuel to the surface of the particles so that these particles will not have a dry, dusty nature. In any event, the pressure preferably should be considerably heavier than that used in the formation of ordinary commercial briquets, such additional pressure having the important function of producing a dense mass of heavy weight which successfully resists the entrance of moisture. This .is highly important because moisture in the. briquet ren ders very difiicult the successful reconversion of the fuel into a combustible powder by my process. The pulverizing and briquetting operations above described may be performed at the coal mine or at the coal yard, or at any other suitable point remote from the point where the fuel is to be burned, and the blocks or briquets thus prepared may be easily transported to the point of use and stored in a bin. There is no liability of the fuel in this condition exploding, and, therefore, it is perfectly safe to store it in a home,apartment house, or any other desired place.

In burning the fuel, I may employ any of the well-known types of pulverized fuel burners, and I take the blocks or briquets and, by suitable apparatus, scrape or shave or abrade the fuel from the blocks in pulverized form at the proper rate required by the burner. The apparatus for scraping or shaving or abrading the fuel from the blocks should be of such a nature as to reduce the fuel to the proper degree of fineness for perfect combustion, and this pulverized fuel is then immediately introduced into a blast of air which conveys it to the burner in the usual manner.

The advantage in this method of preparing the fuel for the burner is that the fuel throughout the blocks or briquets will be of uniform'density' or structure so that as the pulverized fuel is removed from the blocks it will be uniform in character'and also may be removed at a uniform rate.

One advantage in subjecting the blocks, in the briquetting operation, to a suflicient pressure to bring the oil in the fuel to the surface of the particles is that this oil then acts more or less as a lubricant for the apparatus which scrapes or shaves off the par- 1. The method of preparin solid fuel for burning as pulverized fuel w ic-h consists in initially pulverizing the fuel, then compressing the pulverized fuel into briquets, and then removing said pulverized fuel from the surfaces of the briquets and immediately delivering the same to a burner.

2. The method of preparing solid fuel for burning as pulverized fuel which consists in initially pulverizing the fuel. then mixing the pulverized fuel with a binder and compressing it into briquets, then removing the fuel from the surface of the briquets in a pulverized form suitable for combustion and immediately delivering the thus pulverized fuel into the burner.

3. The method of preparing solid fuel for burning as a pulverized .fuel which consists in initially pulverizing the fuel, then mixbriquets, and then removing the fuel from the surface of the briquets in pulverized form and introducing it into a current of air which immediately delivers the fuel to the burner.

5 A briquet made from substantially dr'y solid fuel pulverized to a uniform fineness and heavily compressed to' form a dense substantially moisture-free'and moisture-resisting mass capable of having a powder of umform finenessscraped or abraded from its surface.

6.'A briquet made from soft coal which has been reduced to pulverized form, mixed with a binder, and compressed with suflicient pressure togbring the oil inthe particles of coal to the surface-of these particles.

In testimony whereof, I hereunto afiix my signature.

LEE B. GREEN.

ing the fuel with a binder and compressing 

